/** Used to compose unicode character classes. */
const rsAstralRange = "\\ud800-\\udfff";
const rsComboMarksRange = "\\u0300-\\u036f";
const reComboHalfMarksRange = "\\ufe20-\\ufe2f";
const rsComboSymbolsRange = "\\u20d0-\\u20ff";
const rsComboMarksExtendedRange = "\\u1ab0-\\u1aff";
const rsComboMarksSupplementRange = "\\u1dc0-\\u1dff";
const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange + rsComboMarksExtendedRange + rsComboMarksSupplementRange;
const rsDingbatRange = "\\u2700-\\u27bf";
const rsLowerRange = "a-z\\xdf-\\xf6\\xf8-\\xff";
const rsMathOpRange = "\\xac\\xb1\\xd7\\xf7";
const rsNonCharRange = "\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\xbf";
const rsPunctuationRange = "\\u2000-\\u206f";
const rsSpaceRange = " \\t\\x0b\\f\\xa0\\ufeff\\n\\r\\u2028\\u2029\\u1680\\u180e\\u2000\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008\\u2009\\u200a\\u202f\\u205f\\u3000";
const rsUpperRange = "A-Z\\xc0-\\xd6\\xd8-\\xde";
const rsVarRange = "\\ufe0e\\ufe0f";
const rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;

/** Used to compose unicode capture groups. */
const rsApos = "['\u2019]";
const rsBreak = `[${rsBreakRange}]`;
const rsCombo = `[${rsComboRange}]`;
const rsDigit = "\\d";
const rsDingbat = `[${rsDingbatRange}]`;
const rsLower = `[${rsLowerRange}]`;
const rsMisc = `[^${rsAstralRange}${rsBreakRange + rsDigit + rsDingbatRange + rsLowerRange + rsUpperRange}]`;
const rsFitz = "\\ud83c[\\udffb-\\udfff]";
const rsModifier = `(?:${rsCombo}|${rsFitz})`;
const rsNonAstral = `[^${rsAstralRange}]`;
const rsRegional = "(?:\\ud83c[\\udde6-\\uddff]){2}";
const rsSurrPair = "[\\ud800-\\udbff][\\udc00-\\udfff]";
const rsUpper = `[${rsUpperRange}]`;
const rsZWJ = "\\u200d";

/** Used to compose unicode regexes. */
const rsMiscLower = `(?:${rsLower}|${rsMisc})`;
const rsMiscUpper = `(?:${rsUpper}|${rsMisc})`;
const rsOptContrLower = `(?:${rsApos}(?:d|ll|m|re|s|t|ve))?`;
const rsOptContrUpper = `(?:${rsApos}(?:D|LL|M|RE|S|T|VE))?`;
const reOptMod = `${rsModifier}?`;
const rsOptVar = `[${rsVarRange}]?`;
const rsOptJoin = `(?:${rsZWJ}(?:${[rsNonAstral, rsRegional, rsSurrPair].join("|")})${rsOptVar + reOptMod})*`;
const rsOrdLower = "\\d*(?:1st|2nd|3rd|(?![123])\\dth)(?=\\b|[A-Z_])";
const rsOrdUpper = "\\d*(?:1ST|2ND|3RD|(?![123])\\dTH)(?=\\b|[a-z_])";
const rsSeq = rsOptVar + reOptMod + rsOptJoin;
const rsEmoji = `(?:${[rsDingbat, rsRegional, rsSurrPair].join("|")})${rsSeq}`;

const reUnicodeWords = RegExp([
  `${rsUpper}?${rsLower}+${rsOptContrLower}(?=${[rsBreak, rsUpper, "$"].join("|")})`,
  `${rsMiscUpper}+${rsOptContrUpper}(?=${[rsBreak, rsUpper + rsMiscLower, "$"].join("|")})`,
  `${rsUpper}?${rsMiscLower}+${rsOptContrLower}`,
  `${rsUpper}+${rsOptContrUpper}`,
  rsOrdUpper,
  rsOrdLower,
  `${rsDigit}+`,
  rsEmoji,
].join("|"), "g");

export function matchUnicodeWordsResult(str: string): RegExpMatchArray | null {
  return str.match(reUnicodeWords);
}

